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| -rw-r--r-- | adns-0.6/src/adns.h | 818 |
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diff --git a/adns-0.6/src/adns.h b/adns-0.6/src/adns.h new file mode 100644 index 0000000..588acba --- /dev/null +++ b/adns-0.6/src/adns.h @@ -0,0 +1,818 @@ +/* + * adns.h + * - adns user-visible API (single-threaded, without any locking) + */ +/* + * + * This file is + * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk> + * + * It is part of adns, which is + * Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk> + * Copyright (C) 1999 Tony Finch <dot@dotat.at> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * + * For the benefit of certain LGPL'd `omnibus' software which provides + * a uniform interface to various things including adns, I make the + * following additional licence. I do this because the GPL would + * otherwise force either the omnibus software to be GPL'd or for the + * adns-using part to be distributed separately. + * + * So, you may also redistribute and/or modify adns.h (but only the + * public header file adns.h and not any other part of adns) under the + * terms of the GNU Library General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * Note that adns itself is GPL'd. Authors of adns-using applications + * with GPL-incompatible licences, and people who distribute adns with + * applications where the whole distribution is not GPL'd, are still + * likely to be in violation of the GPL. Anyone who wants to do this + * should contact Ian Jackson. Please note that to avoid encouraging + * people to infringe the GPL as it applies the body of adns, I think + * that if you take advantage of the special exception to redistribute + * just adns.h under the LGPL, you should retain this paragraph in its + * place in the appropriate copyright statements. + * + * + * You should have received a copy of the GNU General Public License, + * or the GNU Library General Public License, as appropriate, along + * with this program; if not, write to the Free Software Foundation, + * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * + * $Id: adns.h,v 1.1.1.1 2000-02-16 17:32:46 sdyoung Exp $ + */ + +#ifndef ADNS_H_INCLUDED +#define ADNS_H_INCLUDED +#ifdef __cplusplus +extern "C" { /* I really dislike this - iwj. */ +#endif + +#include <stdio.h> + +#include <sys/socket.h> +#include <netinet/in.h> +#include <sys/types.h> +#include <sys/time.h> +#include <unistd.h> + +/* All struct in_addr anywhere in adns are in NETWORK byte order. */ + +typedef struct adns__state *adns_state; +typedef struct adns__query *adns_query; + +typedef enum { + adns_if_noenv= 0x0001, /* do not look at environment */ + adns_if_noerrprint= 0x0002, /* never print output to stderr (_debug overrides) */ + adns_if_noserverwarn= 0x0004, /* do not warn to stderr about duff nameservers etc */ + adns_if_debug= 0x0008, /* enable all output to stderr plus debug msgs */ + adns_if_logpid= 0x0080, /* include pid in diagnostic output */ + adns_if_noautosys= 0x0010, /* do not make syscalls at every opportunity */ + adns_if_eintr= 0x0020, /* allow _wait and _synchronous to return EINTR */ + adns_if_nosigpipe= 0x0040, /* applic has SIGPIPE set to SIG_IGN, do not protect */ + adns_if_checkc_entex= 0x0100, /* do consistency checks on entry/exit to adns funcs */ + adns_if_checkc_freq= 0x0300 /* do consistency checks very frequently (slow!) */ +} adns_initflags; + +typedef enum { + adns_qf_search= 0x00000001, /* use the searchlist */ + adns_qf_usevc= 0x00000002, /* use a virtual circuit (TCP connection) */ + adns_qf_owner= 0x00000004, /* fill in the owner field in the answer */ + adns_qf_quoteok_query= 0x00000010, /* allow quote-requiring chars in query domain */ + adns_qf_quoteok_cname= 0x00000000, /* allow ... in CNAME we go via - now default */ + adns_qf_quoteok_anshost= 0x00000040, /* allow ... in things supposed to be hostnames */ + adns_qf_quotefail_cname= 0x00000080, /* refuse if quote-req chars in CNAME we go via */ + adns_qf_cname_loose= 0x00000100, /* allow refs to CNAMEs - without, get _s_cname */ + adns_qf_cname_forbid= 0x00000200, /* don't follow CNAMEs, instead give _s_cname */ + adns__qf_internalmask= 0x0ff00000 +} adns_queryflags; + +typedef enum { + adns__rrt_typemask= 0x0ffff, + adns__qtf_deref= 0x10000, /* dereference domains and perhaps produce extra data */ + adns__qtf_mail822= 0x20000, /* make mailboxes be in RFC822 rcpt field format */ + + adns_r_none= 0, + + adns_r_a= 1, + + adns_r_ns_raw= 2, + adns_r_ns= adns_r_ns_raw|adns__qtf_deref, + + adns_r_cname= 5, + + adns_r_soa_raw= 6, + adns_r_soa= adns_r_soa_raw|adns__qtf_mail822, + + adns_r_ptr_raw= 12, + adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref, + + adns_r_hinfo= 13, + + adns_r_mx_raw= 15, + adns_r_mx= adns_r_mx_raw|adns__qtf_deref, + + adns_r_txt= 16, + + adns_r_rp_raw= 17, + adns_r_rp= adns_r_rp_raw|adns__qtf_mail822, + + adns_r_addr= adns_r_a|adns__qtf_deref + +} adns_rrtype; + +/* + * In queries without qf_quoteok_*, all domains must have standard + * legal syntax, or you get adns_s_querydomainvalid (if the query + * domain contains bad characters) or adns_s_answerdomaininvalid (if + * the answer contains bad characters). + * + * In queries _with_ qf_quoteok_*, domains in the query or response + * may contain any characters, quoted according to RFC1035 5.1. On + * input to adns, the char* is a pointer to the interior of a " + * delimited string, except that " may appear in it, and on output, + * the char* is a pointer to a string which would be legal either + * inside or outside " delimiters, and any characters not usually + * legal in domain names will be quoted as \X (if the character is + * 33-126 except \ and ") or \DDD. + * + * If the query goes via a CNAME then the canonical name (ie, the + * thing that the CNAME record refers to) is usually allowed to + * contain any characters, which will be quoted as above. With + * adns_qf_quotefail_cname you get adns_s_answerdomaininvalid when + * this happens. (This is a change from version 0.4 and earlier, in + * which failing the query was the default, and you had to say + * adns_qf_quoteok_cname to avoid this; that flag is now deprecated.) + * + * In version 0.4 and earlier, asking for _raw records containing + * mailboxes without specifying _qf_quoteok_anshost was silly. This + * is no longer the case. In this version only parts of responses + * that are actually supposed to be hostnames will be refused by + * default if quote-requiring characters are found. + */ + +/* + * If you ask for an RR which contains domains which are actually + * encoded mailboxes, and don't ask for the _raw version, then adns + * returns the mailbox formatted suitably for an RFC822 recipient + * header field. The particular format used is that if the mailbox + * requires quoting according to the rules in RFC822 then the + * local-part is quoted in double quotes, which end at the next + * unescaped double quote. (\ is the escape char, and is doubled, and + * is used to escape only \ and ".) Otherwise the local-part is + * presented as-is. In any case this is followed by an @ and the + * domain. The domain will not contain any characters not legal in + * hostnames. adns will protect the application from local parts + * containing control characters - these appear to be legal according + * to RFC822 but are clearly a bad idea. + * + * If you ask for the domain with _raw then _no_ checking is done + * (even on the host part, regardless of adns_qf_quoteok_anshost), and + * you just get the domain name in master file format. + * + * If no mailbox is supplied the returned string will be `.' in either + * caswe. + */ + +typedef enum { + adns_s_ok, + + /* locally induced errors */ + adns_s_nomemory, + adns_s_unknownrrtype, + adns_s_systemfail, + + adns_s_max_localfail= 29, + + /* remotely induced errors, detected locally */ + adns_s_timeout, + adns_s_allservfail, + adns_s_norecurse, + adns_s_invalidresponse, + adns_s_unknownformat, + + adns_s_max_remotefail= 59, + + /* remotely induced errors, reported by remote server to us */ + adns_s_rcodeservfail, + adns_s_rcodeformaterror, + adns_s_rcodenotimplemented, + adns_s_rcoderefused, + adns_s_rcodeunknown, + + adns_s_max_tempfail= 99, + + /* remote configuration errors */ + adns_s_inconsistent, /* PTR gives domain whose A does not exist and match */ + adns_s_prohibitedcname, /* CNAME found where eg A expected (not if _qf_loosecname) */ + adns_s_answerdomaininvalid, + adns_s_answerdomaintoolong, + adns_s_invaliddata, + + adns_s_max_misconfig= 199, + + /* permanent problems with the query */ + adns_s_querydomainwrong, + adns_s_querydomaininvalid, + adns_s_querydomaintoolong, + + adns_s_max_misquery= 299, + + /* permanent errors */ + adns_s_nxdomain, + adns_s_nodata, + + adns_s_max_permfail= 499 + +} adns_status; + +typedef struct { + int len; + union { + struct sockaddr sa; + struct sockaddr_in inet; + } addr; +} adns_rr_addr; + +typedef struct { + char *host; + adns_status astatus; + int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */ + adns_rr_addr *addrs; +} adns_rr_hostaddr; + +typedef struct { + char *(array[2]); +} adns_rr_strpair; + +typedef struct { + int i; + adns_rr_hostaddr ha; +} adns_rr_inthostaddr; + +typedef struct { + /* Used both for mx_raw, in which case i is the preference and str the domain, + * and for txt, in which case each entry has i for the `text' length, + * and str for the data (which will have had an extra nul appended + * so that if it was plain text it is now a null-terminated string). + */ + int i; + char *str; +} adns_rr_intstr; + +typedef struct { + adns_rr_intstr array[2]; +} adns_rr_intstrpair; + +typedef struct { + char *mname, *rname; + unsigned long serial, refresh, retry, expire, minimum; +} adns_rr_soa; + +typedef struct { + adns_status status; + char *cname; /* always NULL if query was for CNAME records */ + char *owner; /* only set if requested in query flags */ + adns_rrtype type; /* guaranteed to be same as in query */ + time_t expires; /* expiry time, defined only if _s_ok, nxdomain or nodata. NOT TTL! */ + int nrrs, rrsz; /* nrrs is 0 if an error occurs */ + union { + void *untyped; + unsigned char *bytes; + char *(*str); /* ns_raw, cname, ptr, ptr_raw */ + adns_rr_intstr *(*manyistr); /* txt (list of strings ends with i=-1, str=0) */ + adns_rr_addr *addr; /* addr */ + struct in_addr *inaddr; /* a */ + adns_rr_hostaddr *hostaddr; /* ns */ + adns_rr_intstrpair *intstrpair; /* hinfo */ + adns_rr_strpair *strpair; /* rp, rp_raw */ + adns_rr_inthostaddr *inthostaddr; /* mx */ + adns_rr_intstr *intstr; /* mx_raw */ + adns_rr_soa *soa; /* soa, soa_raw */ + } rrs; +} adns_answer; + +/* Memory management: + * adns_state and adns_query are actually pointers to malloc'd state; + * On submission questions are copied, including the owner domain; + * Answers are malloc'd as a single piece of memory; pointers in the + * answer struct point into further memory in the answer. + * query_io: + * Must always be non-null pointer; + * If *query_io is 0 to start with then any query may be returned; + * If *query_io is !0 adns_query then only that query may be returned. + * If the call is successful, *query_io, *answer_r, and *context_r + * will all be set. + * Errors: + * Return values are 0 or an errno value. + * + * For _init, _init_strcfg, _submit and _synchronous, system errors + * (eg, failure to create sockets, malloc failure, etc.) return errno + * values. + * + * For _wait and _check failures are reported in the answer + * structure, and only 0, ESRCH or (for _check) EAGAIN is + * returned: if no (appropriate) requests are done adns_check returns + * EAGAIN; if no (appropriate) requests are outstanding both + * adns_query and adns_wait return ESRCH. + * + * Additionally, _wait can return EINTR if you set adns_if_eintr. + * + * All other errors (nameserver failure, timed out connections, &c) + * are returned in the status field of the answer. After a + * successful _wait or _check, if status is nonzero then nrrs will be + * 0, otherwise it will be >0. type will always be the type + * requested. + */ + +int adns_init(adns_state *newstate_r, adns_initflags flags, + FILE *diagfile /*0=>stderr*/); + +int adns_init_strcfg(adns_state *newstate_r, adns_initflags flags, + FILE *diagfile /*0=>discard*/, const char *configtext); + +/* Configuration: + * adns_init reads /etc/resolv.conf, which is expected to be (broadly + * speaking) in the format expected by libresolv, and then + * /etc/resolv-adns.conf if it exists. adns_init_strcfg is instead + * passed a string which is interpreted as if it were the contents of + * resolv.conf or resolv-adns.conf. In general, configuration which + * is set later overrides any that is set earlier. + * + * Standard directives understood in resolv[-adns].conf: + * + * nameserver <address> + * Must be followed by the IP address of a nameserver. Several + * nameservers may be specified, and they will be tried in the order + * found. There is a compiled in limit, currently 5, on the number + * of nameservers. (libresolv supports only 3 nameservers.) + * + * search <domain> ... + * Specifies the search list for queries which specify + * adns_qf_search. This is a list of domains to append to the query + * domain. The query domain will be tried as-is either before all + * of these or after them, depending on the ndots option setting + * (see below). + * + * domain <domain> + * This is present only for backward compatibility with obsolete + * versions of libresolv. It should not be used, and is interpreted + * by adns as if it were `search' - note that this is subtly + * different to libresolv's interpretation of this directive. + * + * sortlist <addr>/<mask> ... + * Should be followed by a sequence of IP-address and netmask pairs, + * separated by spaces. They may be specified as + * eg. 172.30.206.0/24 or 172.30.206.0/255.255.255.0. Currently up + * to 15 pairs may be specified (but note that libresolv only + * supports up to 10). + * + * options + * Should followed by one or more options, separated by spaces. + * Each option consists of an option name, followed by optionally + * a colon and a value. Options are listed below. + * + * Non-standard directives understood in resolv[-adns].conf: + * + * clearnameservers + * Clears the list of nameservers, so that further nameserver lines + * start again from the beginning. + * + * include <filename> + * The specified file will be read. + * + * Additionally, adns will ignore lines in resolv[-adns].conf which + * start with a #. + * + * Standard options understood: + * + * debug + * Enables debugging output from the resolver, which will be written + * to stderr. + * + * ndots:<count> + * Affects whether queries with adns_qf_search will be tried first + * without adding domains from the searchlist, or whether the bare + * query domain will be tried last. Queries which contain at least + * <count> dots will be tried bare first. The default is 1. + * + * Non-standard options understood: + * + * adns_checkc:none + * adns_checkc:entex + * adns_checkc:freq + * Changes the consistency checking frequency; this overrides the + * setting of adns_if_check_entex, adns_if_check_freq, or neither, + * in the flags passed to adns_init. + * + * There are a number of environment variables which can modify the + * behaviour of adns. They take effect only if adns_init is used, and + * the caller of adns_init can disable them using adns_if_noenv. In + * each case there is both a FOO and an ADNS_FOO; the latter is + * interpreted later so that it can override the former. Unless + * otherwise stated, environment variables are interpreted after + * resolv[-adns].conf are read, in the order they are listed here. + * + * RES_CONF, ADNS_RES_CONF + * A filename, whose contets are in the format of resolv.conf. + * + * RES_CONF_TEXT, ADNS_RES_CONF_TEXT + * A string in the format of resolv.conf. + * + * RES_OPTIONS, ADNS_RES_OPTIONS + * These are parsed as if they appeared in the `options' line of a + * resolv.conf. In addition to being parsed at this point in the + * sequence, they are also parsed at the very beginning before + * resolv.conf or any other environment variables are read, so that + * any debug option can affect the processing of the configuration. + * + * LOCALDOMAIN, ADNS_LOCALDOMAIN + * These are interpreted as if their contents appeared in a `search' + * line in resolv.conf. + */ + +int adns_synchronous(adns_state ads, + const char *owner, + adns_rrtype type, + adns_queryflags flags, + adns_answer **answer_r); + +/* NB: if you set adns_if_noautosys then _submit and _check do not + * make any system calls; you must use some of the asynch-io event + * processing functions to actually get things to happen. + */ + +int adns_submit(adns_state ads, + const char *owner, + adns_rrtype type, + adns_queryflags flags, + void *context, + adns_query *query_r); + +/* The owner should be quoted in master file format. */ + +int adns_check(adns_state ads, + adns_query *query_io, + adns_answer **answer_r, + void **context_r); + +int adns_wait(adns_state ads, + adns_query *query_io, + adns_answer **answer_r, + void **context_r); + +/* same as adns_wait but uses poll(2) internally */ +int adns_wait_poll(adns_state ads, + adns_query *query_io, + adns_answer **answer_r, + void **context_r); + +void adns_cancel(adns_query query); + +/* The adns_query you get back from _submit is valid (ie, can be + * legitimately passed into adns functions) until it is returned by + * adns_check or adns_wait, or passed to adns_cancel. After that it + * must not be used. You can rely on it not being reused until the + * first adns_submit or _transact call using the same adns_state after + * it became invalid, so you may compare it for equality with other + * query handles until you next call _query or _transact. + * + * _submit and _synchronous return ENOSYS if they don't understand the + * query type. + */ + +int adns_submit_reverse(adns_state ads, + const struct sockaddr *addr, + adns_rrtype type, + adns_queryflags flags, + void *context, + adns_query *query_r); +/* type must be _r_ptr or _r_ptr_raw. _qf_search is ignored. + * addr->sa_family must be AF_INET or you get ENOSYS. + */ + +void adns_finish(adns_state ads); +/* You may call this even if you have queries outstanding; + * they will be cancelled. + */ + + +void adns_forallqueries_begin(adns_state ads); +adns_query adns_forallqueries_next(adns_state ads, void **context_r); +/* Iterator functions, which you can use to loop over the outstanding + * (submitted but not yet successfuly checked/waited) queries. + * + * You can only have one iteration going at once. You may call _begin + * at any time; after that, an iteration will be in progress. You may + * only call _next when an iteration is in progress - anything else + * may coredump. The iteration remains in progress until _next + * returns 0, indicating that all the queries have been walked over, + * or ANY other adns function is called with the same adns_state (or a + * query in the same adns_state). There is no need to explicitly + * finish an iteration. + * + * context_r may be 0. *context_r may not be set when _next returns 0. + */ + +void adns_checkconsistency(adns_state ads, adns_query qu); +/* Checks the consistency of adns's internal data structures. + * If any error is found, the program will abort(). + * You may pass 0 for qu; if you pass non-null then additional checks + * are done to make sure that qu is a valid query. + */ + +/* + * Example expected/legal calling sequence for submit/check/wait: + * adns_init + * adns_submit 1 + * adns_submit 2 + * adns_submit 3 + * adns_wait 1 + * adns_check 3 -> EAGAIN + * adns_wait 2 + * adns_wait 3 + * .... + * adns_finish + */ + +/* + * Entrypoints for generic asynch io: + * (these entrypoints are not very useful except in combination with * + * some of the other I/O model calls which can tell you which fds to + * be interested in): + * + * Note that any adns call may cause adns to open and close fds, so + * you must call beforeselect or beforepoll again just before + * blocking, or you may not have an up-to-date list of it's fds. + */ + +int adns_processany(adns_state ads); +/* Gives adns flow-of-control for a bit. This will never block, and + * can be used with any threading/asynch-io model. If some error + * occurred which might cause an event loop to spin then the errno + * value is returned. + */ + +int adns_processreadable(adns_state ads, int fd, const struct timeval *now); +int adns_processwriteable(adns_state ads, int fd, const struct timeval *now); +int adns_processexceptional(adns_state ads, int fd, const struct timeval *now); +/* Gives adns flow-of-control so that it can process incoming data + * from, or send outgoing data via, fd. Very like _processany. If it + * returns zero then fd will no longer be readable or writeable + * (unless of course more data has arrived since). adns will _only_ + * use that fd and only in the manner specified, regardless of whether + * adns_if_noautosys was specified. + * + * adns_processexceptional should be called when select(2) reports an + * exceptional condition, or poll(2) reports POLLPRI. + * + * It is fine to call _processreabable or _processwriteable when the + * fd is not ready, or with an fd that doesn't belong to adns; it will + * then just return 0. + * + * If some error occurred which might prevent an event loop to spin + * then the errno value is returned. + */ + +void adns_processtimeouts(adns_state ads, const struct timeval *now); +/* Gives adns flow-of-control so that it can process any timeouts + * which might have happened. Very like _processreadable/writeable. + * + * now may be 0; if it isn't, *now must be the current time, recently + * obtained from gettimeofday. + */ + +void adns_firsttimeout(adns_state ads, + struct timeval **tv_mod, struct timeval *tv_buf, + struct timeval now); +/* Asks adns when it would first like the opportunity to time + * something out. now must be the current time, from gettimeofday. + * + * If tv_mod points to 0 then tv_buf must be non-null, and + * _firsttimeout will fill in *tv_buf with the time until the first + * timeout, and make *tv_mod point to tv_buf. If adns doesn't have + * anything that might need timing out it will leave *tv_mod as 0. + * + * If *tv_mod is not 0 then tv_buf is not used. adns will update + * *tv_mod if it has any earlier timeout, and leave it alone if it + * doesn't. + * + * This call will not actually do any I/O, or change the fds that adns + * is using. It always succeeds and never blocks. + */ + +void adns_globalsystemfailure(adns_state ads); +/* If serious problem(s) happen which globally affect your ability to + * interact properly with adns, or adns's ability to function + * properly, you or adns can call this function. + * + * All currently outstanding queries will be made to fail with + * adns_s_systemfail, and adns will close any stream sockets it has + * open. + * + * This is used by adns, for example, if gettimeofday() fails. + * Without this the program's event loop might start to spin ! + * + * This call will never block. + */ + +/* + * Entrypoints for select-loop based asynch io: + */ + +void adns_beforeselect(adns_state ads, int *maxfd, fd_set *readfds, + fd_set *writefds, fd_set *exceptfds, + struct timeval **tv_mod, struct timeval *tv_buf, + const struct timeval *now); +/* Find out file descriptors adns is interested in, and when it would + * like the opportunity to time something out. If you do not plan to + * block then tv_mod may be 0. Otherwise, tv_mod and tv_buf are as + * for adns_firsttimeout. readfds, writefds, exceptfds and maxfd_io may + * not be 0. + * + * If *now is not 0 then this will never actually do any I/O, or + * change the fds that adns is using or the timeouts it wants. In any + * case it won't block. + */ + +void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds, + const fd_set *writefds, const fd_set *exceptfds, + const struct timeval *now); +/* Gives adns flow-of-control for a bit; intended for use after + * select. This is just a fancy way of calling adns_processreadable/ + * writeable/timeouts as appropriate, as if select had returned the + * data being passed. Always succeeds. + */ + +/* + * Example calling sequence: + * + * adns_init _noautosys + * loop { + * adns_beforeselect + * select + * adns_afterselect + * ... + * adns_submit / adns_check + * ... + * } + */ + +/* + * Entrypoints for poll-loop based asynch io: + */ + +struct pollfd; +/* In case your system doesn't have it or you forgot to include + * <sys/poll.h>, to stop the following declarations from causing + * problems. If your system doesn't have poll then the following + * entrypoints will not be defined in libadns. Sorry ! + */ + +int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io, int *timeout_io, + const struct timeval *now); +/* Finds out which fd's adns is interested in, and when it would like + * to be able to time things out. This is in a form suitable for use + * with poll(2). + * + * On entry, usually fds should point to at least *nfds_io structs. + * adns will fill up to that many structs will information for poll, + * and record in *nfds_io how many structs it filled. If it wants to + * listen for more structs then *nfds_io will be set to the number + * required and _beforepoll will return ERANGE. + * + * You may call _beforepoll with fds==0 and *nfds_io 0, in which case + * adns will fill in the number of fds that it might be interested in + * in *nfds_io, and always return either 0 (if it is not interested in + * any fds) or ERANGE (if it is). + * + * NOTE that (unless now is 0) adns may acquire additional fds + * from one call to the next, so you must put adns_beforepoll in a + * loop, rather than assuming that the second call (with the buffer + * size requested by the first) will not return ERANGE. + * + * adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd + * structs, and only ever looks at those bits. POLLPRI is required to + * detect TCP Urgent Data (which should not be used by a DNS server) + * so that adns can know that the TCP stream is now useless. + * + * In any case, *timeout_io should be a timeout value as for poll(2), + * which adns will modify downwards as required. If the caller does + * not plan to block then *timeout_io should be 0 on entry, or + * alternatively, timeout_io may be 0. (Alternatively, the caller may + * use _beforeselect with timeout_io==0 to find out about file + * descriptors, and use _firsttimeout is used to find out when adns + * might want to time something out.) + * + * adns_beforepoll will return 0 on success, and will not fail for any + * reason other than the fds buffer being too small (ERANGE). + * + * This call will never actually do any I/O. If you supply the + * current time it will not change the fds that adns is using or the + * timeouts it wants. + * + * In any case this call won't block. + */ + +#define ADNS_POLLFDS_RECOMMENDED 2 +/* If you allocate an fds buf with at least RECOMMENDED entries then + * you are unlikely to need to enlarge it. You are recommended to do + * so if it's convenient. However, you must be prepared for adns to + * require more space than this. + */ + +void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds, + const struct timeval *now); +/* Gives adns flow-of-control for a bit; intended for use after + * poll(2). fds and nfds should be the results from poll(). pollfd + * structs mentioning fds not belonging to adns will be ignored. + */ + + +adns_status adns_rr_info(adns_rrtype type, + const char **rrtname_r, const char **fmtname_r, + int *len_r, + const void *datap, char **data_r); +/* + * Get information about a query type, or convert reply data to a + * textual form. type must be specified, and the official name of the + * corresponding RR type will be returned in *rrtname_r, and + * information about the processing style in *fmtname_r. The length + * of the table entry in an answer for that type will be returned in + * in *len_r. Any or all of rrtname_r, fmtname_r and len_r may be 0. + * If fmtname_r is non-null then *fmtname_r may be null on return, + * indicating that no special processing is involved. + * + * data_r be must be non-null iff datap is. In this case *data_r will + * be set to point to a string pointing to a representation of the RR + * data in master file format. (The owner name, timeout, class and + * type will not be present - only the data part of the RR.) The + * memory will have been obtained from malloc() and must be freed by + * the caller. + * + * Usually this routine will succeed. Possible errors include: + * adns_s_nomemory + * adns_s_rrtypeunknown + * adns_s_invaliddata (*datap contained garbage) + * If an error occurs then no memory has been allocated, + * and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined. + * + * There are some adns-invented data formats which are not official + * master file formats. These include: + * + * Mailboxes if __qtf_mail822: these are just included as-is. + * + * Addresses (adns_rr_addr): these may be of pretty much any type. + * The representation is in two parts: first, a word for the address + * family (ie, in AF_XXX, the XXX), and then one or more items for the + * address itself, depending on the format. For an IPv4 address the + * syntax is INET followed by the dotted quad (from inet_ntoa). + * Currently only IPv4 is supported. + * + * Text strings (as in adns_rr_txt) appear inside double quotes, and + * use \" and \\ to represent " and \, and \xHH to represent + * characters not in the range 32-126. + * + * Hostname with addresses (adns_rr_hostaddr): this consists of the + * hostname, as usual, followed by the adns_status value, as an + * abbreviation, and then a descriptive string (encoded as if it were + * a piece of text), for the address lookup, followed by zero or more + * addresses enclosed in ( and ). If the result was a permanent + * failure, then a single ? appears instead of the ( ). If the + * result was a temporary failure then an empty pair of parentheses + * appears (which a space in between). For example, one of the NS + * records for greenend.org.uk comes out like + * ns.chiark.greenend.org.uk ok "OK" ( INET 195.224.76.132 ) + * an MX referring to a nonexistent host might come out like: + * 50 sun2.nsfnet-relay.ac.uk nxdomain "No such domain" ( ) + * and if nameserver information is not available you might get: + * dns2.spong.dyn.ml.org timeout "DNS query timed out" ? + */ + +const char *adns_strerror(adns_status st); +const char *adns_errabbrev(adns_status st); +const char *adns_errtypeabbrev(adns_status st); +/* Like strerror but for adns_status values. adns_errabbrev returns + * the abbreviation of the error - eg, for adns_s_timeout it returns + * "timeout". adns_errtypeabbrev returns the abbreviation of the + * error class: ie, for values up to adns_s_max_XXX it will return the + * string XXX. You MUST NOT call these functions with status values + * not returned by the same adns library. + */ + +#ifdef __cplusplus +} /* end of extern "C" */ +#endif +#endif |